Mountain Lion Clean Install or Upgrade for rMBP?

Discussion in 'OS X Mountain Lion (10.8)' started by diversity83, Jul 26, 2012.

  1. diversity83 macrumors newbie

    Jul 26, 2012
    Los Angeles, CA
    I understand that Clean Install is typically the way to go for the smoothest transition to a new OS, but I’m wondering if it’s really necessary for my rMBP. I just got it this week and I haven’t really done much with it since I was waiting for Mountain Lion to launch. When I say, “haven’t really done much”, I’m referring to not doing any installations of software and applications, setting up email, adding photos/videos, etc.. I thought by keeping it default as possible that the upgrade path would be just fine. Is that the case?

    I will appreciate all responses with your opinions and/or recommendations. Also, if I were to go with the “Clean Install” route, can someone please give me step-by-step instructions as to how I can wipe my SSD to do an Internet Recovery of the ML OS? I booted with Command+R and went to disk utilities, but that’s where I get lost. I don’t’ know what to wipe… I see the SSD and other sub sections that I don’t know what to erase.

    Thanks in advance guys/gals!
  2. GGJstudios macrumors Westmere


    May 16, 2008
  3. Sir Al macrumors member

    Sir Al

    Feb 14, 2005
    Vancouver, Canada
    I have a rMBP that I've been using for just over a week. I plan to do an upgrade to Mountain Lion. There's no reason to do a "clean install", even though I've installed a bunch of stuff, but very little has changed to the operating system itself. You might save a few megabytes of space by doing a clean install from any files left over, but it'll be minimal if any.

    There's just no reason to go the hassle with a clean install. Mac OS X is designed really well that the plists scale to an upgrade quite nicely. Each system component reads the necessary keys, and any new ones get added automatically, and the updated/upgraded plist is written back "like new" with just some options that perhaps you have set changed from the default. There is no "registry" that can get fragmented and littered with old, unused keys. The directory structure is designed very well such that the System folder for the old OS can simply be moved aside, and a new one put in place. You can delete the old System folder after if you want.

    Check the /Library folder for any Lion-only stuff if you like, but chances are that it will have only application specific stuff that if you were to do a clean install would simply get re-populated exactly as before during re-installation of apps if you hadn't done a clean install. Those are the two folders that will be affected during a clean install, unless you want to start with a new user account also, which is up to you. I found the upgrade process in Mail, iCal, Address Book, etc, to be great. You can look at their respective databases for old databases that have been upgraded if you want to delete the old, unused databases to save space. I don't bother with starting a new user account anymore as I end up moving back most of the data in my old user account anyway.

    Unless you really have nothing you want to move over and want a fresh system, an upgrade will save you time and no downsides in terms of performance or functionality from what I've experienced.

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